Note 9 - Share-based Compensation - Summary of Option Activity Under Stock Plans (Details) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2024	Mar. 31, 2024
Outstanding (in shares)		297,000
Outstanding, weighted average exercise price (in dollars per share)		$ 2.47
Outstanding, weighted average remaining contractual term (Year)		6 years 10 months 24 days	7 years 1 month 6 days
Outstanding, aggregate intrinsic value	$ 0	$ 0	$ 0
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)	0	50,000
Granted, weighted average exercise price (in dollars per share)		$ 0.78
Expired (in shares)		(25,000)
Expired, weighted average exercise price (in dollars per share)		$ 2.57
Outstanding (in shares)	322,000	322,000	297,000
Outstanding, weighted average exercise price (in dollars per share)	$ 2.2	$ 2.2	$ 2.47
Exercisable (in shares)	222,000	222,000
Exercisable, weighted average exercise price (in dollars per share)	$ 2.64	$ 2.64
Exercisable, weighted average remaining contractual term (Year)		6 years